Tchau is a brazilian portuguese word that means "bye". It's used just in Brazil, an still very popular. It's derived from the italian word "Ciao", when the italian imigrants arrived in Brazil. Everyone in Brazil knows what it means.

An informal portuguese word used both in Brazil and Portugal, altough it is more common in Brazil.

It is derived from the italian word "Ciao", a salute that means either "Hello" or "Goodbye". However, in Brazil and Portugal, it is rarely used as an initial greeting - instead, it is a common substitute for the word "Adeus" - "Goodbye" in Portuguese.

The word was largely spread by italian emigrants who brought their culture, including linguistic terms, to all over the world, especially to the South American countries - Colombia, Brazil, Uruguai, Bolivia, Argentina, Venezuela, etc. It is still a very common word in Brazil.

In Portugal, the word is still in usage but it's not as common as in Brazil. In fact, in the Portuguese slang, the word "Tchau" has acquired a slighty different meaning from the original, since it is often used to respond with amusement or fright to a fantastic or unexpected statement, very much similar to the english expressions "Get out of here" or "You don't say so...".